By Scout Nelson
Herbicide drift is a major concern for vineyard growers because grapevines are highly sensitive to many herbicides. Even small amounts of drifting spray or vapor can damage leaves, reduce vine growth, and affect future production. The damage may come from herbicide applications inside the vineyard or from nearby fields.
The type of damage depends on the herbicide involved, the amount that reaches the vines, weather conditions, and whether the herbicide moves as spray droplets or vapor. Growers who understand these differences can identify problems earlier and take the right action to protect their vineyards.
Several herbicide groups can injure grapevines. Auxin herbicides, including 2,4-D, dicamba, picloram, triclopyr, and clopyralid, often cause twisted leaves, cupping, and abnormal growth.
ALS-inhibitor herbicides, such as trisulfuron-methyl, imazapyr, and chlorsulfuron, also damage grape growth. Glyphosate, an EPSP synthase inhibitor, can cause yellowing, poor growth, and leaf injury because it blocks important plant processes.
Symptoms vary, but growers commonly notice chlorosis (yellow leaves), epinasty (downward bending leaves), leaf feathering, leaf strapping, leaf stacking, mottled chlorosis, and shoe-stringing, where leaves become narrow, stretched, and distorted. Learning these terms helps growers identify possible herbicide injury more accurately.
Preventing herbicide drift is the best way to protect vineyards. Growers can register their vineyards with DriftWatch at https://driftwatch.org/ so pesticide applicators know the locations of sensitive crops. It is also helpful to communicate regularly with neighboring farmers and local highway departments about spray plans.
When establishing new vineyards, selecting sites away from large row crop fields may reduce drift risk. Planting tree buffer strips along vineyard borders can also help limit off-site drift.
Within vineyards, growers should carefully select herbicides based on vine age and growth stage. Some products are suitable only for mature vines, while others may safely manage grapevine suckers when used correctly.
If herbicide drift is suspected, Minnesota growers should report the incident to the Minnesota Department of Agriculture (MDA) as soon as possible. Early reporting helps investigators collect evidence, document damage, and support future management decisions or legal action if necessary.
Photo Credit: istock-jhvephoto
Categories: Minnesota, General